Do cams have any markings to identify the maker, and the specs for the cam? Maybe on the timing face? I have two engines. One a complete rebuild on a stand, but the owner passed away, and the family does not have any info. The second a low mile rebuild in a vehicle, but again family does not have any info. The fella was a hot rodder for sure but would like to see what I am working with before I jam it in a car.

Second question - how can you tell if a cylinder head has been milled? Is there a reference point I can measure to see where I am at or do I have to CC the chambers?

Cam grinders usually stamp their ID info. on the rear of the cam.

As for the head... it will measure 3.600 thick in factory condition.
( deck surface to valve cover gasket surface)

Over-all thickness is just a quick reference point, you really need to cc a chamber to know where you are with compression on any cylinder head you have.
DD